Prism-glass.



PATENTBD APR.- 17, 1906.

vF. L. O WADSWORTH.

PRISM GLASS. APPLICATION FILED JUNE 17, 1005 INVENTOR WITNESSES Ui rrE-n STATES.

PATENT OFFICE.

FRANK L. O. WADSWORTH, OF MORGANTOWN, WEST VIRGINIA, ASSIGNOH TO PRESSED PRISM PLATE GLASS COMPANY, OF NEIV YORK. N. .Y., A CORPORATION OF WEST VIRGINIA.

PRISM-GLASS.

Specification of Letters Patent.

Patented April 17, 1906.

Application filed June 17, 1905. Serial No. 265,808.

.To all whom it' may concern.-

won'rH, of Morgantown, Monongalia county, West Virginia, have invented a new and useful Prism-Glass, of which the following is a full, clear, and exact description, reference being had to the aecom anying drawings,

V forming part of this speci 'cation, in which Figure 1 shows a prism-glass sheet set in a pivoted or movable canopy-frame and embodying my invention. Fig. 2 is a vertical section of the sheet in a plane parallel with the rib, and Fig. 3 is a vertical section in a plane at right angles to the sectional plane of Fig. 2.

In the manufacture of plates of prism-glass in which the prisms are formed by parallel ribs difficulty has been experienced from the I fact that in a direction at right angles to the ribs the plate has only the strength of the main body of the glass, and when the plates are large this difiiculty becomes serious, requiring them to be made of extra thickness in order to meet the rules of the insurance companies.

I have discovered that the sheets may be strengthened and rendered more capable of resisting breaking strains no matter in what direction it may be applied by providing them on the prism-surface w th ribs which are preferably prismatic it eneral outline and preferably also of thexsame height as the prisms themselves, so that ti ir apices will be flush therewith. These ribs are transverse to the lines of the prisms, preferably at right angles thereto, and their effect is to strengthen the glass sheet, so that in every direction it will have substantiany the same strength as if it possessed throughout the full thickness of the body portion plus the height of the prisms. Therefore in order to obtain a plate of given strength the body of the glass plate 2 can be made much thinner than heretofore, and as a consequence the plate will be lighter and can be set in a lighter supportingframe. The reduction of weight of the glass is of great practical im ortance where it is to be used in movable s ylights and canopies, where light weight renders the structures less cumbersome and easy to handle and'safer to use because of the lessened liability to breakcanopy. 2 is the body of the glass plate, 3 3 Be it known that I, FRANK L. O. WADS- are the parallel prism projections, and 4 4 preferably made triangular in cross-section, and to render the plate easier to clean they are preferably curved or filleted at their bases, as at b.' Their apices are preferably flush with theapices of the prism projections, and when made of prismatic form they constitute to a certain extent a second series of prisms, so that the glass plate will refract the light not only in a vertical direction like an ordinary prism-glass plate, but also in a lateral direction. This is important and dcsirable on account of the broad range of illumination which it affords.

Prism-plates made in accordance. with my invention present abeautifulappearance, as the cross-ribs break up the monotony of the continuous prisms and impart a brilliant cutglass effect.

My invention also prevents the well-known o tical illusion which is present with prismsiderable lengthand by which the prisms appear to be non-parallel and irregular. The transverse strengthenin -ribs by breaking up the prisms into relatively short lengths prevents such illusion.

My prism-glass plates are preferably made by rolling a mass of glass into sheet form and while it is still plastic bringing a die thereon and pressing in one operation the prism projections and the transverse strengtheningribs. This method of manufacture is de. scribed fully in a prior patent, No. 661,025, granted to l). C. Ripley and myself on October30, 1900, for improvement in the manufacture of prism-glass.

The form of the projections and their arrangement will be modified in many ways within the scope of my invention as broadly claimed, since What I claim is 1. As anewarticle of manufacture. aprismglass plate having a continuous prism-surface and having on the prism -i"ace transverse strengthening-ribs.

2. As a new article of manufacture, uprisinglass plate having a conti nuous prisin-siirface and having on the prism -face transverse strengthening-ribs at right angles to he prism projections.

are the strengthening-ribs. These latter are g ass having continuous prisms of any con- 3. As a new article of manufacture, aprismglass plate havmg a contlnuous prism-surface and having on the prism-face transverse 1 5. As a new article of manufacture, a prismglass plate having a continuous prism-surface and having on the prism-face transverse strengthening-ribs prismatic in cross-section and adapted to refract the light transversely.

In estimony whereof I have hereuntc set-- my hand. FRANK L. O. WADSWORTH. Witnesses:

THOMAS W. BAKEWELL, H. M. CoRWIN. 

